LOS ANGELES (AP) — The red-hot U.S. housing market is paying off for many homeowners, even those who aren’t looking to sell their home.

On average, homes with a mortgage gained $26,300 in equity in the last three months of 2020 versus a year earlier, according to real estate information company CoreLogic. That average gain is the highest since 2013, the firm said.

CoreLogic said homes with a mortgage account for about 62% of all U.S. properties. Taken together, the home equity for those properties surged to more than $1.5 trillion, an increase of 16.2% from a year earlier.

The surge in homeowners’ equity can potentially make a positive impact on borrowers’ finances; for one thing, it creates a buffer against potential financial hardship, such as job loss. And homeowners could opt to put some of the gains to use, giving a boost to the economy.

“In our view, these strong equity gains are a clear positive for homeowner balance sheets, as well as for overall additional consumer spending, should homeowners be desirous of tapping a portion of their equity gains,” Jonathan Woloshin, a real estate and lodging analyst at UBS, wrote in a research note last week.

Rising home values and low mortgage rates spurred many U.S. homeowners to refinance and cash in some of the equity in their home last year. Homeowners pulled out $152.7 billion in equity, an increase of 41.7% from 2019 and the highest refinancing cash-out dollar amount since 2007, according to mortgage buyer Freddie Mac.

Homeowners also tapped into the equity in their home via a home equity line of credit, or HELOC. The volume of HELOCs more than doubled in 2020 from a year earlier to $74.9 billion.

Low mortgage rates, strong demand and a record low inventory of homes for sale nationwide have fueled home sales and pushed home prices higher since last summer.

Sales of previously occupied U.S. homes climbed 5.6% in 2020 from a year earlier to 5.64 million, the highest level since 2006 at the height of the housing boom, according to the National Association of Realtors. The national median home sales price jumped 12.9% to $309,800.

The strong demand for homes continued in January, with sales ticking up 0.6% from December and almost 24% from a year earlier. By the end of January, however, the supply of homes on the market nationally was down to a record-low 1.04 million units. That amounts to a 1.9 months’ supply. A balanced housing market tends to have a 6-month supply. The Realtors group issues its February home sales data next week.

When home equity rises, it reduces the risk that a homeowner with a mortgage will end up “underwater” on their loan, meaning they owe more on their mortgage than their home is worth. That can happen when a home’s value declines, or when the size of the mortgage increases, say when someone takes out a home equity loan.

Homes in California, Idaho and Washington saw among the biggest average increases in annual equity gains in the fourth quarter: $54,500 in California, $48,500 in Idaho and $47,000 in Washington state, CoreLogic said.

Even a robust housing market with rising prices can’t limit the risk of a homeowner ending up underwater on their home loan entirely.

In the fourth quarter, some 410,000 U.S. residential properties were underwater on their mortgage, according to CoreLogic. That’s a 21% decline from the same period in 2019, when 1.9 million homes, or 3.6% of all properties with a mortgage, were in negative equity, the firm said.

Miami, Miami Beach and the suburb of Kendall, Florida, had an average negative home equity share that was among the biggest nationally at 6.3%.

The underwater mortgages at the end of December represent roughly $280.2 billion in mortgage debt, down 2.6% from a year earlier, CoreLogic said.

When a mortgage is underwater, the homeowner often can’t qualify for mortgage refinancing and has little recourse but to continue making payments in hopes the property eventually regains its value.

Many economists expect home prices to continue rising this year, which bodes well for homeowners with underwater mortgages. Should U.S. home prices increase by 5%, then some 216,000 homes would regain equity, CoreLogic said. If the reverse happens, nearly 300,000 homes would slip into negative equity, the firm said.